// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package org.apache.tapestry5.ioc.services;
import org.apache.tapestry5.ioc.MethodAdviceReceiver;
/**
* An advisor that identifies methods which can be evaluated lazily and advises them. A method can be evaluated lazily
* if it returns an interface type and if it throws no checked exceptions. Lazy evaluation should be handled carefully,
* as if any of the parameters to a method are mutable, or the internal state of the invoked service changes, the lazily
* evaluated results may not match the immediately evaluated result. This effect is greatly exaggerated if the lazy
* return object is evaluated in a different thread than when it was generated.
*
* Another consideration is that exceptions that would occur immediately in the non-lazy case are also deferred, often
* losing much context in the process.
*
* Use laziness with great care.
*
* Use the {@link org.apache.tapestry5.ioc.annotations.NotLazy} annotation on methods that should not be advised.
*
* @since 5.1.0.0
*/
public interface LazyAdvisor
{
void addLazyMethodInvocationAdvice(MethodAdviceReceiver methodAdviceReceiver);
}